This invention relates to a start control device in a fuel supply system for an internal combustion engine.
In a conventional air-fuel ratio control system 1, as shown in FIG. 1, for controlling an amount of bleed air to be supplied to a slow fuel system and a main fuel system in a carburetor, moisture formed in a combustion chamber 2 by fuel combustion sometimes flows upstream in an air intake pipe 3 or water vapor contained in atmosphere is cooled to form water droplets between needle valves 4 and jets 5. In particular, when the engine is left to stand at low temperatures such as in a cold district, the water droplets are frozen to render the needle valves unoperable. As a result, during the next engine start operation, even when an actuator 7 receives a signal as to close the jets 5 from a control circuit 6, the needle valves 4 cannot move and the jets 5 are held in their opened position. Thusly, the air-fuel ratio of air-and-fuel mixture to be supplied to the engine becomes lean and accordingly, the engine start operation cannot be readily conducted.
In another case where the actuator 7 or the control circuit 6 fails to work during non-use of a vehicle and the needle valves 4 of the actuator 7 cannot be returned to their predetermined start position, the air-fuel ratio of air-and-fuel mixture to be supplied to the engine becomes lean and accordingly, the engine start operation cannot be readily conducted.